Nano-Chinese herbal medicines and their delivery strategies for central nervous system disease therapy

Central nervous system (CNS) diseases, including neurodegenerative diseases, stroke, brain tumors, and others, result in poor quality of life and can cause substantial disability. Not all CNS diseases are amenable to surgical approaches, so drug development is important for disease treatment. Unfortunately, there are few drugs currently available for CNS diseases. Chinese herbal medicines (CHMs), represented by herb derived active ingredients and decoctions, have long been used in the treatment of CNS diseases. One of the major challenges in the further development of CHMs for CNS diseases is to improve cerebral drug delivery, and nanotechnology applied to CHMs to obtain nano-Chinese Herbal Medicines (nano-CHMs) is an effective way. This review categorizes nano-CHMs according to their preparation methods and sources, and discusses the applications of each nano-CHM and its advantages. Considering the special status of the brain, we further summarize the delivery strategies of nano-CHMs and the physiological barriers that need to be overcome for different strategies. Finally, we discuss the application of nano-CHMs for various CNS diseases, aiming to provide insights into the development of nano-CHMs for the treatment of CNS diseases.